All pairs of domain combinations at the superfamily level are listed here.
The identification of domain pairs does not account for the possibility of non-contiguous domains. Inserted, or interlaced, domains are seen as having a simple pair ordering.
The links below permit the addition or removal of specific sets of domain combination pairs.
Change the list of genome two-letter codes in the 'Include genomes' box to include domain-pairs from those genomes.
Change the list of genomes in the 'Exclude genomes' box to exclude domain-pairs from those genomes.
List of all two-letter genome codes.
| Superfamily (N) | Superfamily (C) | Number of occurrances | Number unique | |
| P-loop containing nucleoside triphosphate hydrolases | P-loop containing nucleoside triphosphate hydrolases | 24 | 9 |  |
| lambda repressor-like DNA-binding domains | Periplasmic binding protein-like I | 9 | 1 |  |
| ABC transporter transmembrane region | P-loop containing nucleoside triphosphate hydrolases | 8 | 4 |  |
| Actin-like ATPase domain | Actin-like ATPase domain | 7 | 5 |  |
| CheY-like | C-terminal effector domain of the bipartite response regulators | 6 | 1 |  |
| NAD(P)-binding Rossmann-fold domains | 6-phosphogluconate dehydrogenase C-terminal domain-like | 6 | 2 |  |
| Nucleotidylyl transferase | Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases | 6 | 5 |  |
| (Trans)glycosidases | Glycosyl hydrolase domain | 6 | 6 |  |
| PreATP-grasp domain | Glutathione synthetase ATP-binding domain-like | 6 | 4 |  |
| NAD(P)-binding Rossmann-fold domains | Glyceraldehyde-3-phosphate dehydrogenase-like, C-terminal domain | 5 | 2 |  |
| MurD-like peptide ligases, catalytic domain | MurD-like peptide ligases, peptide-binding domain | 5 | 5 |  |
| P-loop containing nucleoside triphosphate hydrolases | Translation proteins | 5 | 4 |  |
| Ribosomal protein S5 domain 2-like | GHMP Kinase, C-terminal domain | 5 | 4 |  |
| (Trans)glycosidases | E set domains | 5 | 4 |  |
| Multidrug resistance efflux transporter EmrE | Multidrug resistance efflux transporter EmrE | 4 | 2 |  |
| Homodimeric domain of signal transducing histidine kinase | ATPase domain of HSP90 chaperone/DNA topoisomerase II/histidine kinase | 4 | 3 |  |
| "Winged helix" DNA-binding domain | Actin-like ATPase domain | 4 | 3 |  |
| PreATP-grasp domain | Rudiment single hybrid motif | 4 | 2 |  |
| Glutathione synthetase ATP-binding domain-like | Rudiment single hybrid motif | 4 | 2 |  |
| Class II aaRS and biotin synthetases | Class II aaRS ABD-related | 4 | 3 |  |
| Composite domain of metallo-dependent hydrolases | Metallo-dependent hydrolases | 3 | 3 |  |
| HAD-like | Calcium ATPase, transmembrane domain M | 3 | 1 |  |
| Nucleic acid-binding proteins | Class II aaRS and biotin synthetases | 3 | 3 |  |
| EF-G C-terminal domain-like | EF-G C-terminal domain-like | 3 | 2 |  |
| Calcium ATPase, transduction domain A | Calcium ATPase, transmembrane domain M | 3 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | EF-G C-terminal domain-like | 3 | 2 |  |
| ValRS/IleRS/LeuRS editing domain | Nucleotidylyl transferase | 3 | 2 |  |
| Thiamin diphosphate-binding fold (THDP-binding) | Thiamin diphosphate-binding fold (THDP-binding) | 3 | 3 |  |
| Metal cation-transporting ATPase, ATP-binding domain N | Calcium ATPase, transmembrane domain M | 3 | 1 |  |
| cAMP-binding domain-like | "Winged helix" DNA-binding domain | 3 | 1 |  |
| Glycosyl hydrolase domain | E set domains | 3 | 3 |  |
| Thiolase-like | Thiolase-like | 3 | 3 |  |
| P-loop containing nucleoside triphosphate hydrolases | Ribosomal protein S5 domain 2-like | 3 | 3 |  |
| ValRS/IleRS/LeuRS editing domain | Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases | 3 | 2 |  |
| Metal cation-transporting ATPase, ATP-binding domain N | HAD-like | 3 | 1 |  |
| Calcium ATPase, transduction domain A | HAD-like | 3 | 1 |  |
| Calcium ATPase, transduction domain A | Metal cation-transporting ATPase, ATP-binding domain N | 3 | 1 |  |
| Translation proteins | EF-G C-terminal domain-like | 3 | 2 |  |
| (Trans)glycosidases | Galactose mutarotase-like | 2 | 2 |  |
| MurCD N-terminal domain | MurD-like peptide ligases, catalytic domain | 2 | 2 |  |
| Ribokinase-like | Thiamin phosphate synthase | 2 | 1 |  |
| Zn-dependent exopeptidases | Bacterial exopeptidase dimerisation domain | 2 | 1 |  |
| "Winged helix" DNA-binding domain | GntR ligand-binding domain-like | 2 | 1 |  |
| Galactose-binding domain-like | Galactose mutarotase-like | 2 | 2 |  |
| P-loop containing nucleoside triphosphate hydrolases | "Winged helix" DNA-binding domain | 2 | 2 |  |
| ATPase domain of HSP90 chaperone/DNA topoisomerase II/histidine kinase | Ribosomal protein S5 domain 2-like | 2 | 2 |  |
| P-loop containing nucleoside triphosphate hydrolases | C-terminal domain of alpha and beta subunits of F1 ATP synthase | 2 | 2 |  |
| ATPase domain of HSP90 chaperone/DNA topoisomerase II/histidine kinase | Type II DNA topoisomerase | 2 | 2 |  |
| Nucleic acid-binding proteins | P-loop containing nucleoside triphosphate hydrolases | 2 | 2 |  |
| Chaperone J-domain | HSP40/DnaJ peptide-binding domain | 2 | 2 |  |
| Double Clp-N motif | P-loop containing nucleoside triphosphate hydrolases | 2 | 1 |  |
| MurE/MurF N-terminal domain | MurD-like peptide ligases, catalytic domain | 2 | 2 |  |
| Aminoacid dehydrogenase-like, N-terminal domain | NAD(P)-binding Rossmann-fold domains | 2 | 1 |  |
| beta-Galactosidase/glucuronidase domain | Galactose mutarotase-like | 2 | 2 |  |
| MurCD N-terminal domain | MurD-like peptide ligases, peptide-binding domain | 2 | 2 |  |
| MalF N-terminal region-like | MetI-like | 2 | 2 |  |
| Type II DNA topoisomerase | GyrA/ParC C-terminal domain-like | 2 | 1 |  |
| PurM N-terminal domain-like | PurM C-terminal domain-like | 2 | 2 |  |
| Phosphoglucomutase, first 3 domains | Phosphoglucomutase, C-terminal domain | 2 | 2 |  |
| Nucleic acid-binding proteins | Nucleic acid-binding proteins | 2 | 2 |  |
| Nucleic acid-binding proteins | RuvA domain 2-like | 2 | 2 |  |
| tRNA-binding arm | Class II aaRS and biotin synthetases | 2 | 1 |  |
| HSP40/DnaJ peptide-binding domain | HSP40/DnaJ peptide-binding domain | 2 | 2 |  |
| Glutamine synthetase, N-terminal domain | Glutamine synthetase/guanido kinase | 2 | 1 |  |
| Ribosomal protein S5 domain 2-like | Ribonuclease PH domain 2-like | 2 | 2 |  |
| NAD(P)-binding Rossmann-fold domains | LDH C-terminal domain-like | 2 | 1 |  |
| beta-Galactosidase/glucuronidase domain | beta-Galactosidase/glucuronidase domain | 2 | 2 |  |
| CBS-domain pair | FAD-binding/transporter-associated domain-like | 2 | 1 |  |
| Galactose-binding domain-like | (Trans)glycosidases | 2 | 2 |  |
| N-terminal domain of alpha and beta subunits of F1 ATP synthase | P-loop containing nucleoside triphosphate hydrolases | 2 | 2 |  |
| Galactose-binding domain-like | beta-Galactosidase/glucuronidase domain | 2 | 2 |  |
| HAMP domain-like | Homodimeric domain of signal transducing histidine kinase | 2 | 2 |  |
| Lysozyme-like | beta-lactamase/transpeptidase-like | 2 | 2 |  |
| Translation proteins SH3-like domain | Nucleic acid-binding proteins | 2 | 2 |  |
| Class II aaRS and biotin synthetases | ThrRS/AlaRS common domain | 2 | 2 |  |
| Phosphoglucomutase, first 3 domains | Phosphoglucomutase, first 3 domains | 2 | 2 |  |
| Ribosomal protein S5 domain 2-like | Type II DNA topoisomerase | 2 | 2 |  |
| Alpha-L RNA-binding motif | Pseudouridine synthase | 2 | 1 |  |
| Enolase N-terminal domain-like | Enolase C-terminal domain-like | 2 | 1 |  |
| MurE/MurF N-terminal domain | MurD-like peptide ligases, peptide-binding domain | 2 | 2 |  |
| N-terminal domain of alpha and beta subunits of F1 ATP synthase | C-terminal domain of alpha and beta subunits of F1 ATP synthase | 2 | 2 |  |
| HIT-like | HIT-like | 2 | 1 |  |
| "Winged helix" DNA-binding domain | Periplasmic binding protein-like II | 2 | 1 |  |
| beta-Galactosidase/glucuronidase domain | (Trans)glycosidases | 2 | 2 |  |
| Ribosomal protein S5 domain 2-like | EF-G C-terminal domain-like | 2 | 2 |  |
| "Winged helix" DNA-binding domain | NagB/RpiA/CoA transferase-like | 2 | 1 |  |
| HAMP domain-like | ATPase domain of HSP90 chaperone/DNA topoisomerase II/histidine kinase | 2 | 2 |  |
| Formate/glycerate dehydrogenase catalytic domain-like | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| Bacterial immunoglobulin/albumin-binding domains | Bacterial immunoglobulin/albumin-binding domains | 1 | 1 |  |
| PGBD-like | (Trans)glycosidases | 1 | 1 |  |
| Polynucleotide phosphorylase/guanosine pentaphosphate synthase (PNPase/GPSI), domain 3 | Nucleic acid-binding proteins | 1 | 1 |  |
| Glycoside hydrolase/deacetylase | Galactose mutarotase-like | 1 | 1 |  |
| UBA-like | Elongation factor Ts (EF-Ts), dimerisation domain | 1 | 1 |  |
| 5' to 3' exonuclease, C-terminal subdomain | DNA/RNA polymerases | 1 | 1 |  |
| Succinate dehydrogenase/fumarate reductase flavoprotein, catalytic domain | Succinate dehydrogenase/fumarate reductase flavoprotein C-terminal domain | 1 | 1 |  |
| DnaJ/Hsp40 cysteine-rich domain | HSP40/DnaJ peptide-binding domain | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Class I glutamine amidotransferase-like | 1 | 1 |  |
| MetI-like | P-loop containing nucleoside triphosphate hydrolases | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Obg GTP-binding protein C-terminal domain | 1 | 1 |  |
| Prokaryotic type KH domain (KH-domain type II) | Ribosomal protein S3 C-terminal domain | 1 | 1 |  |
| Nucleic acid-binding proteins | ArfGap/RecO-like zinc finger | 1 | 1 |  |
| Nucleic acid-binding proteins | Anticodon-binding domain of PheRS | 1 | 1 |  |
| Probable ACP-binding domain of malonyl-CoA ACP transacylase | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| Thiamin pyrophosphokinase, catalytic domain | Thiamin pyrophosphokinase, substrate-binding domain | 1 | 1 |  |
| Carbon-nitrogen hydrolase | Adenine nucleotide alpha hydrolases-like | 1 | 1 |  |
| Nucleic acid-binding proteins | DNA helicase RuvA subunit, C-terminal domain | 1 | 1 |  |
| Domain of the SRP/SRP receptor G-proteins | P-loop containing nucleoside triphosphate hydrolases | 1 | 1 |  |
| Acyl-CoA N-acyltransferases (Nat) | Acyl-CoA N-acyltransferases (Nat) | 1 | 1 |  |
| FKBP-like | Triger factor/SurA peptide-binding domain-like | 1 | 1 |  |
| Glutathione synthetase ATP-binding domain-like | Carbamoyl phosphate synthetase, large subunit connection domain | 1 | 1 |  |
| Putative anticodon-binding domain of alanyl-tRNA synthetase (AlaRS) | Translation proteins | 1 | 1 |  |
| FAD/NAD(P)-binding domain | FAD-linked reductases, C-terminal domain | 1 | 1 |  |
| 5' to 3' exonuclease, C-terminal subdomain | Ribonuclease H-like | 1 | 1 |  |
| FAD/NAD(P)-binding domain | FAD/NAD-linked reductases, dimerisation (C-terminal) domain | 1 | 1 |  |
| Glutathione synthetase ATP-binding domain-like | Glutathione synthetase ATP-binding domain-like | 1 | 1 |  |
| Tubulin nucleotide-binding domain-like | Tubulin C-terminal domain-like | 1 | 1 |  |
| Periplasmic binding protein-like II | ACT-like | 1 | 1 |  |
| Obg GTP-binding protein N-terminal domain | P-loop containing nucleoside triphosphate hydrolases | 1 | 1 |  |
| PLP-binding barrel | Alanine racemase C-terminal domain-like | 1 | 1 |  |
| PIN domain-like | Ribonuclease H-like | 1 | 1 |  |
| FAD/NAD(P)-binding domain | Succinate dehydrogenase/fumarate reductase flavoprotein, catalytic domain | 1 | 1 |  |
| FAD/NAD(P)-binding domain | Succinate dehydrogenase/fumarate reductase flavoprotein C-terminal domain | 1 | 1 |  |
| Carbamoyl phosphate synthetase, large subunit connection domain | Methylglyoxal synthase-like | 1 | 1 |  |
| Inosine monophosphate dehydrogenase (IMPDH) | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| Putative anticodon-binding domain of alanyl-tRNA synthetase (AlaRS) | ThrRS/AlaRS common domain | 1 | 1 |  |
| Nucleotide-diphospho-sugar transferases | Trimeric LpxA-like enzymes | 1 | 1 |  |
| Thioesterase/thiol ester dehydrase-isomerase | Thiolase-like | 1 | 1 |  |
| Starch-binding domain-like | E set domains | 1 | 1 |  |
| Class II aaRS and biotin synthetases | YbaK/ProRS associated domain | 1 | 1 |  |
| Rho N-terminal domain-like | P-loop containing nucleoside triphosphate hydrolases | 1 | 1 |  |
| Translation proteins | ThrRS/AlaRS common domain | 1 | 1 |  |
| GreA transcript cleavage protein, N-terminal domain | FKBP-like | 1 | 1 |  |
| Methionyl-tRNA synthetase (MetRS), Zn-domain | Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases | 1 | 1 |  |
| PK beta-barrel domain-like | PK C-terminal domain-like | 1 | 1 |  |
| GIY-YIG endonuclease | C-terminal UvrC-binding domain of UvrB | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | RecA protein, C-terminal domain | 1 | 1 |  |
| Class I glutamine amidotransferase-like | Adenine nucleotide alpha hydrolases-like | 1 | 1 |  |
| Nucleotidyltransferase | Poly A polymerase C-terminal region-like | 1 | 1 |  |
| PRTase-like | PRTase-like | 1 | 1 |  |
| Class I glutamine amidotransferase-like | GMP synthetase C-terminal dimerisation domain | 1 | 1 |  |
| PreATP-grasp domain | PreATP-grasp domain | 1 | 1 |  |
| Nucleic acid-binding proteins | Prokaryotic type KH domain (KH-domain type II) | 1 | 1 |  |
| NAD-binding domain of HMG-CoA reductase | Substrate-binding domain of HMG-CoA reductase | 1 | 1 |  |
| DNA ligase/mRNA capping enzyme, catalytic domain | BRCT domain | 1 | 1 |  |
| ParB/Sulfiredoxin | KorB DNA-binding domain-like | 1 | 1 |  |
| YbaK/ProRS associated domain | Class II aaRS ABD-related | 1 | 1 |  |
| PheT/TilS domain | Anticodon-binding domain of PheRS | 1 | 1 |  |
| Alpha-L RNA-binding motif | S-adenosyl-L-methionine-dependent methyltransferases | 1 | 1 |  |
| (Trans)glycosidases | (Trans)glycosidases | 1 | 1 |  |
| Phospholipase D/nuclease | Phospholipase D/nuclease | 1 | 1 |  |
| PreATP-grasp domain | Single hybrid motif | 1 | 1 |  |
| Trypsin-like serine proteases | PDZ domain-like | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | MOP-like | 1 | 1 |  |
| ThrRS/AlaRS common domain | Class II aaRS ABD-related | 1 | 1 |  |
| Obg GTP-binding protein N-terminal domain | Obg GTP-binding protein C-terminal domain | 1 | 1 |  |
| Nucleotidyltransferase | Nucleotidyltransferase | 1 | 1 |  |
| "Winged helix" DNA-binding domain | C-terminal domain of arginine repressor | 1 | 1 |  |
| Aspartate/ornithine carbamoyltransferase | Aspartate carbamoyltransferase, Regulatory-chain, C-terminal domain | 1 | 1 |  |
| Creatinase/prolidase N-terminal domain | Creatinase/aminopeptidase | 1 | 1 |  |
| TGS-like | ACT-like | 1 | 1 |  |
| GroEL equatorial domain-like | GroEL apical domain-like | 1 | 1 |  |
| dsRNA-binding domain-like | Ribosomal protein S5 domain 2-like | 1 | 1 |  |
| Putative DNA-binding domain | Antibiotic binding domain of TipA-like multidrug resistance regulators | 1 | 1 |  |
| FabD/lysophospholipase-like | Inosine monophosphate dehydrogenase (IMPDH) | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Restriction endonuclease-like | 1 | 1 |  |
| Eukaryotic type KH-domain (KH-domain type I) | Nucleic acid-binding proteins | 1 | 1 |  |
| Nicotinate/Quinolinate PRTase N-terminal domain-like | Nicotinate/Quinolinate PRTase C-terminal domain-like | 1 | 1 |  |
| Inosine monophosphate dehydrogenase (IMPDH) | Thioesterase/thiol ester dehydrase-isomerase | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | TrpR-like | 1 | 1 |  |
| ClpP/crotonase | ClpP/crotonase | 1 | 1 |  |
| Actin-like ATPase domain | Heat shock protein 70kD (HSP70), peptide-binding domain | 1 | 1 |  |
| Translation proteins | Ribosomal protein S5 domain 2-like | 1 | 1 |  |
| FabD/lysophospholipase-like | Probable ACP-binding domain of malonyl-CoA ACP transacylase | 1 | 1 |  |
| GHMP Kinase, C-terminal domain | FMN-linked oxidoreductases | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | post-AAA+ oligomerization domain-like | 1 | 1 |  |
| Concanavalin A-like lectins/glucanases | Sialidases | 1 | 1 |  |
| Penicillin binding protein dimerisation domain | beta-lactamase/transpeptidase-like | 1 | 1 |  |
| 2Fe-2S ferredoxin-like | alpha-helical ferredoxin | 1 | 1 |  |
| Probable ACP-binding domain of malonyl-CoA ACP transacylase | Inosine monophosphate dehydrogenase (IMPDH) | 1 | 1 |  |
| Putative DNA-binding domain | Anticodon-binding domain of PheRS | 1 | 1 |  |
| Rho N-terminal domain-like | Nucleic acid-binding proteins | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | CarD-like | 1 | 1 |  |
| HD-domain/PDEase-like | TGS-like | 1 | 1 |  |
| Sigma2 domain of RNA polymerase sigma factors | Sigma3 and sigma4 domains of RNA polymerase sigma factors | 1 | 1 |  |
| Trigger factor ribosome-binding domain | Triger factor/SurA peptide-binding domain-like | 1 | 1 |  |
| Nucleic acid-binding proteins | GAD domain-like | 1 | 1 |  |
| Ribosomal L11/L12e N-terminal domain | Ribosomal protein L11, C-terminal domain | 1 | 1 |  |
| Glutathione synthetase ATP-binding domain-like | Single hybrid motif | 1 | 1 |  |
| Adenine nucleotide alpha hydrolases-like | Adenine nucleotide alpha hydrolases-like | 1 | 1 |  |
| Probable ACP-binding domain of malonyl-CoA ACP transacylase | Thioesterase/thiol ester dehydrase-isomerase | 1 | 1 |  |
| S-adenosyl-L-methionine-dependent methyltransferases | Putative methyltransferase TM0872, insert domain | 1 | 1 |  |
| "Winged helix" DNA-binding domain | GAF domain-like | 1 | 1 |  |
| NagB/RpiA/CoA transferase-like | D-ribose-5-phosphate isomerase (RpiA), lid domain | 1 | 1 |  |
| Trigger factor ribosome-binding domain | FKBP-like | 1 | 1 |  |
| Translation proteins | Initiation factor IF2/eIF5b, domain 3 | 1 | 1 |  |
| R1 subunit of ribonucleotide reductase, N-terminal domain | PFL-like glycyl radical enzymes | 1 | 1 |  |
| Nucleotidylyl transferase | Riboflavin kinase-like | 1 | 1 |  |
| PheT/TilS domain | Putative DNA-binding domain | 1 | 1 |  |
| FucI/AraA N-terminal and middle domains | FucI/AraA C-terminal domain-like | 1 | 1 |  |
| "Winged helix" DNA-binding domain | Dimeric alpha+beta barrel | 1 | 1 |  |
| N-terminal nucleophile aminohydrolases (Ntn hydrolases) | SIS domain | 1 | 1 |  |
| TSP type-3 repeat | alpha/beta-Hydrolases | 1 | 1 |  |
| Carbamoyl phosphate synthetase, small subunit N-terminal domain | Class I glutamine amidotransferase-like | 1 | 1 |  |
| PA domain | Subtilisin-like | 1 | 1 |  |
| Translation proteins | EF-Tu/eEF-1alpha/eIF2-gamma C-terminal domain | 1 | 1 |  |
| Starch-binding domain-like | Starch-binding domain-like | 1 | 1 |  |
| Thioredoxin-like | FAD/NAD(P)-binding domain | 1 | 1 |  |
| L30e-like | alpha/beta knot | 1 | 1 |  |
| PurM C-terminal domain-like | Class I glutamine amidotransferase-like | 1 | 1 |  |
| L9 N-domain-like | Ribosomal protein L9 C-domain | 1 | 1 |  |
| Insert subdomain of RNA polymerase alpha subunit | RBP11-like subunits of RNA polymerase | 1 | 1 |  |
| Putative DNA-binding domain | Class II aaRS and biotin synthetases | 1 | 1 |  |
| Adenine nucleotide alpha hydrolases-like | GMP synthetase C-terminal dimerisation domain | 1 | 1 |  |
| DNA methylase specificity domain | DNA methylase specificity domain | 1 | 1 |  |
| DNA ligase/mRNA capping enzyme, catalytic domain | Nucleic acid-binding proteins | 1 | 1 |  |
| Transcription factor NusA, N-terminal domain | Nucleic acid-binding proteins | 1 | 1 |  |
| Aspartate/glutamate racemase | Aspartate/glutamate racemase | 1 | 1 |  |
| Nucleotidyltransferase substrate binding subunit/domain | Nucleotidyltransferase substrate binding subunit/domain | 1 | 1 |  |
| Coiled-coil domain of nucleotide exchange factor GrpE | Head domain of nucleotide exchange factor GrpE | 1 | 1 |  |
| Arginyl-tRNA synthetase (ArgRS), N-terminal 'additional' domain | Anticodon-binding domain of a subclass of class I aminoacyl-tRNA synthetases | 1 | 1 |  |
| RBP11-like subunits of RNA polymerase | C-terminal domain of RNA polymerase alpha subunit | 1 | 1 |  |
| Chaperone J-domain | DnaJ/Hsp40 cysteine-rich domain | 1 | 1 |  |
| Nucleic acid-binding proteins | S-adenosyl-L-methionine-dependent methyltransferases | 1 | 1 |  |
| Translation proteins | PRC-barrel domain | 1 | 1 |  |
| Glycoside hydrolase/deacetylase | Families 57/38 glycoside transferase middle domain | 1 | 1 |  |
| PreATP-grasp domain | Carbamoyl phosphate synthetase, large subunit connection domain | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Signal peptide-binding domain | 1 | 1 |  |
| N-terminal domain of DnaB helicase | P-loop containing nucleoside triphosphate hydrolases | 1 | 1 |  |
| FAD-binding/transporter-associated domain-like | Uridine diphospho-N-Acetylenolpyruvylglucosamine reductase, MurB, C-terminal domain | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Helical scaffold and wing domains of SecA | 1 | 1 |  |
| ParB/Sulfiredoxin | S-adenosyl-L-methionine-dependent methyltransferases | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | FtsH protease domain-like | 1 | 1 |  |
| PIN domain-like | DNA/RNA polymerases | 1 | 1 |  |
| ALDH-like | Dehydroquinate synthase-like | 1 | 1 |  |
| Translation initiation factor IF3, N-terminal domain | Translation initiation factor IF3, C-terminal domain | 1 | 1 |  |
| "Winged helix" DNA-binding domain | Ribokinase-like | 1 | 1 |  |
| Nucleotidyltransferase | ACT-like | 1 | 1 |  |
| Thioesterase/thiol ester dehydrase-isomerase | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| Fe-S cluster assembly (FSCA) domain-like | P-loop containing nucleoside triphosphate hydrolases | 1 | 1 |  |
| N-terminal nucleophile aminohydrolases (Ntn hydrolases) | PRTase-like | 1 | 1 |  |
| Ribosomal protein S5 domain 2-like | Ribosomal protein S5 domain 2-like | 1 | 1 |  |
| Thiamin diphosphate-binding fold (THDP-binding) | TK C-terminal domain-like | 1 | 1 |  |
| RmlC-like cupins | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| Glycosyl hydrolase domain | Starch-binding domain-like | 1 | 1 |  |
| Ribonuclease PH domain 2-like | Nucleic acid-binding proteins | 1 | 1 |  |
| ABC transporter transmembrane region | ABC transporter transmembrane region | 1 | 1 |  |
| Nucleic acid-binding proteins | BRCT domain | 1 | 1 |  |
| Riboflavin kinase-like | Riboflavin kinase-like | 1 | 1 |  |
| Carbamate kinase-like | PUA domain-like | 1 | 1 |  |
| (Trans)glycosidases | Starch-binding domain-like | 1 | 1 |  |
| Actin-like ATPase domain | Heat shock protein 70kD (HSP70), C-terminal subdomain | 1 | 1 |  |
| CBS-domain pair | Inosine monophosphate dehydrogenase (IMPDH) | 1 | 1 |  |
| Arginyl-tRNA synthetase (ArgRS), N-terminal 'additional' domain | Nucleotidylyl transferase | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | TGS-like | 1 | 1 |  |
| Adenine nucleotide alpha hydrolases-like | MesJ substrate recognition domain-like | 1 | 1 |  |
| RuvA domain 2-like | BRCT domain | 1 | 1 |  |
| ITPase-like | Nudix | 1 | 1 |  |
| Nucleotidylyl transferase | An anticodon-binding domain of class I aminoacyl-tRNA synthetases | 1 | 1 |  |
| Inosine monophosphate dehydrogenase (IMPDH) | Thiolase-like | 1 | 1 |  |
| UROD/MetE-like | UROD/MetE-like | 1 | 1 |  |
| Ribonuclease PH domain 2-like | Ribonuclease PH domain 2-like | 1 | 1 |  |
| S-adenosylmethionine synthetase | S-adenosylmethionine synthetase | 1 | 1 |  |
| Probable ACP-binding domain of malonyl-CoA ACP transacylase | Thiolase-like | 1 | 1 |  |
| DNA ligase/mRNA capping enzyme, catalytic domain | RuvA domain 2-like | 1 | 1 |  |
| Methionyl-tRNA synthetase (MetRS), Zn-domain | Nucleotidylyl transferase | 1 | 1 |  |
| PurM N-terminal domain-like | Class I glutamine amidotransferase-like | 1 | 1 |  |
| Peptidase/esterase 'gauge' domain | alpha/beta-Hydrolases | 1 | 1 |  |
| PheT/TilS domain | Class II aaRS and biotin synthetases | 1 | 1 |  |
| Nucleic acid-binding proteins | Putative DNA-binding domain | 1 | 1 |  |
| Thioredoxin-like | TPR-like | 1 | 1 |  |
| C-terminal UvrC-binding domain of UvrB | RuvA domain 2-like | 1 | 1 |  |
| HD-domain/PDEase-like | Nucleotidyltransferase | 1 | 1 |  |
| Rudiment single hybrid motif | Single hybrid motif | 1 | 1 |  |
| GroES-like | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| "Winged helix" DNA-binding domain | LexA/Signal peptidase | 1 | 1 |  |
| Restriction endonuclease-like | Restriction endonuclease-like | 1 | 1 |  |
| Composite domain of metallo-dependent hydrolases | Composite domain of metallo-dependent hydrolases | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | EF-Tu/eEF-1alpha/eIF2-gamma C-terminal domain | 1 | 1 |  |
| Heat shock protein 70kD (HSP70), peptide-binding domain | Heat shock protein 70kD (HSP70), C-terminal subdomain | 1 | 1 |  |
| CarD-like | TRCF domain-like | 1 | 1 |  |
| FabD/lysophospholipase-like | Thioesterase/thiol ester dehydrase-isomerase | 1 | 1 |  |
| Ribonuclease PH domain 2-like | Eukaryotic type KH-domain (KH-domain type I) | 1 | 1 |  |
| Ribosomal protein S5 domain 2-like | Eukaryotic type KH-domain (KH-domain type I) | 1 | 1 |  |
| FabD/lysophospholipase-like | FabD/lysophospholipase-like | 1 | 1 |  |
| DNA/RNA polymerases | Lesion bypass DNA polymerase (Y-family), little finger domain | 1 | 1 |  |
| PPK N-terminal domain-like | PHP14-like | 1 | 1 |  |
| Nucleotidyltransferase | TGS-like | 1 | 1 |  |
| Insert subdomain of RNA polymerase alpha subunit | C-terminal domain of RNA polymerase alpha subunit | 1 | 1 |  |
| PHP14-like | Phospholipase D/nuclease | 1 | 1 |  |
| Ribonuclease PH domain 2-like | Polynucleotide phosphorylase/guanosine pentaphosphate synthase (PNPase/GPSI), domain 3 | 1 | 1 |  |
| PK beta-barrel domain-like | Phosphoenolpyruvate/pyruvate domain | 1 | 1 |  |
| Adenine nucleotide alpha hydrolases-like | Argininosuccinate synthetase, C-terminal domain | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | C-terminal UvrC-binding domain of UvrB | 1 | 1 |  |
| PIN domain-like | 5' to 3' exonuclease, C-terminal subdomain | 1 | 1 |  |
| Glutamine synthetase/guanido kinase | GatB/YqeY motif | 1 | 1 |  |
| Transcription factor NusA, N-terminal domain | Prokaryotic type KH domain (KH-domain type II) | 1 | 1 |  |
| MetI-like | MetI-like | 1 | 1 |  |
| Cation efflux protein transmembrane domain-like | Cation efflux protein cytoplasmic domain-like | 1 | 1 |  |
| Riboflavin synthase domain-like | Ferredoxin reductase-like, C-terminal NADP-linked domain | 1 | 1 |  |
| PPK N-terminal domain-like | Phospholipase D/nuclease | 1 | 1 |  |
| ITPase-like | ITPase-like | 1 | 1 |  |
| Class II aaRS and biotin synthetases | Putative anticodon-binding domain of alanyl-tRNA synthetase (AlaRS) | 1 | 1 |  |
| Ammonium transporter | Ammonium transporter | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Dehydroquinate synthase-like | 1 | 1 |  |
| Ribosomal protein S5 domain 2-like | FMN-linked oxidoreductases | 1 | 1 |  |
| Polynucleotide phosphorylase/guanosine pentaphosphate synthase (PNPase/GPSI), domain 3 | Eukaryotic type KH-domain (KH-domain type I) | 1 | 1 |  |
| Methyl-accepting chemotaxis protein (MCP) signaling domain | Adhesin YadA, collagen-binding domain | 1 | 1 |  |
| Zinc beta-ribbon | DNA primase core | 1 | 1 |  |
| Nucleic acid-binding proteins | PheT/TilS domain | 1 | 1 |  |
| Phosphoenolpyruvate/pyruvate domain | PK C-terminal domain-like | 1 | 1 |  |
| Glutathione synthetase ATP-binding domain-like | Methylglyoxal synthase-like | 1 | 1 |  |
| NAD(P)-binding Rossmann-fold domains | Thiolase-like | 1 | 1 |  |
| HD-domain/PDEase-like | ACT-like | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Prokaryotic type KH domain (KH-domain type II) | 1 | 1 |  |
| Ribosomal protein L7/12, oligomerisation (N-terminal) domain | ClpS-like | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Pre-protein crosslinking domain of SecA | 1 | 1 |  |
| "Winged helix" DNA-binding domain | Chorismate lyase-like | 1 | 1 |  |
| Class II aaRS and biotin synthetases | GAD domain-like | 1 | 1 |  |
| DNA clamp | DNA clamp | 1 | 1 |  |
| Thioredoxin-like | Thioredoxin-like | 1 | 1 |  |
| Formyltransferase | FMT C-terminal domain-like | 1 | 1 |  |
| PurM N-terminal domain-like | PurM N-terminal domain-like | 1 | 1 |  |
| GroEL equatorial domain-like | GroEL-intermediate domain like | 1 | 1 |  |
| RNase III domain-like | dsRNA-binding domain-like | 1 | 1 |  |
| Pre-protein crosslinking domain of SecA | Helical scaffold and wing domains of SecA | 1 | 1 |  |
| Ribosomal protein S5 domain 2-like | Nucleic acid-binding proteins | 1 | 1 |  |
| Class II aaRS and biotin synthetases | Anticodon-binding domain of PheRS | 1 | 1 |  |
| Nucleotidyltransferase | Nucleotidyltransferase substrate binding subunit/domain | 1 | 1 |  |
| RuvA domain 2-like | DNA helicase RuvA subunit, C-terminal domain | 1 | 1 |  |
| Translation proteins | Translation proteins | 1 | 1 |  |
| FabD/lysophospholipase-like | Thiolase-like | 1 | 1 |  |
| Class II aaRS and biotin synthetases | Translation proteins | 1 | 1 |  |
| Ribosomal protein L6 | Ribosomal protein L6 | 1 | 1 |  |
| Thiamin diphosphate-binding fold (THDP-binding) | DHS-like NAD/FAD-binding domain | 1 | 1 |  |
| Ribonuclease H-like | DNA/RNA polymerases | 1 | 1 |  |
| GroEL-intermediate domain like | GroEL apical domain-like | 1 | 1 |  |
| E set domains | E set domains | 1 | 1 |  |
| FabD/lysophospholipase-like | NAD(P)-binding Rossmann-fold domains | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | Initiation factor IF2/eIF5b, domain 3 | 1 | 1 |  |
| Nudix | Phosphoglycerate mutase-like | 1 | 1 |  |
| Sigma3 and sigma4 domains of RNA polymerase sigma factors | Sigma3 and sigma4 domains of RNA polymerase sigma factors | 1 | 1 |  |
| Families 57/38 glycoside transferase middle domain | Galactose mutarotase-like | 1 | 1 |  |
| Nucleotidylyl transferase | Alpha-L RNA-binding motif | 1 | 1 |  |
| Prokaryotic type KH domain (KH-domain type II) | Prokaryotic type KH domain (KH-domain type II) | 1 | 1 |  |
| PreATP-grasp domain | Methylglyoxal synthase-like | 1 | 1 |  |
| Galactose mutarotase-like | Six-hairpin glycosidases | 1 | 1 |  |
| GIY-YIG endonuclease | RuvA domain 2-like | 1 | 1 |  |
| Ribonuclease H-like | HRDC-like | 1 | 1 |  |
| Ribosomal protein S5 domain 2-like | Polynucleotide phosphorylase/guanosine pentaphosphate synthase (PNPase/GPSI), domain 3 | 1 | 1 |  |
| Methylglyoxal synthase-like | Cytidine deaminase-like | 1 | 1 |  |
| Leukotriene A4 hydrolase N-terminal domain | Metalloproteases ("zincins"), catalytic domain | 1 | 1 |  |
| N-utilization substance G protein NusG, N-terminal domain | Translation proteins SH3-like domain | 1 | 1 |  |
| P-loop containing nucleoside triphosphate hydrolases | TRCF domain-like | 1 | 1 |  |
| beta-N-acetylhexosaminidase-like domain | (Trans)glycosidases | 1 | 1 |  |
| PUA domain-like | alpha/beta knot | 1 | 1 |  |